This invention is in the field of amplitude modulators for laser beams. The known modulators run the gamut from variable density filters to acousto-optic (AO) and electro-optic (EO) devices. At present, insofar as response time and efficiency are concerned, AO and EO devices are preferred, although both are very lossy (20%-60%). Moreover, they each generate two output beams, such that even the beam power remaining after the internal losses is split in half. The present invention overcomes these disadvantages by the new of an old device to effect laser beam amplitude modulation. This old device is a colinear acousto-optic tunable filter.